The association between marriage and positive outcomes for children and adults has been documented in numerous studies. Children of married parents have better educational and health outcomes; married adults have higher earnings and better health. Marriage may, in fact, improve public health. However, cohabitation is increasing in the United States and ubiquitous in Sweden. Given the increased prevalence of cohabitation in both countries, understanding its impact on child and adult outcomes is important in terms of theoretical predictions about the benefits of marriage and policies designed to promote marriage. The goal of this research is to compare the effects of cohabitation and legal marriage on child and adult outcomes in Sweden. In particular, we seek to identify the causal effect of marriage on outcomes by using two empirical approaches a) a quasi-natural experiment-changes in the Swedish Widow's Pension-to examine the impact of a policy-induced change in marital status; and b) sibling and individual fixed effects models to estimate the effect of a change in marital status on child and adult outcomes. We seek support to address the following research questions: 1) What is the correlation of cohabitating family structures compared with married family structures on child educational and health outcomes 2) Is cohabitation correlated with improved adult earnings and health outcomes when compared to marriage? 3) What is the causal effect of marriage on child and adult outcomes? 4) Does marriage have a positive impact on child and adult outcomes when it results from a change in policy? 5) Does the type of selection into marriage (self-selection compared with response to policy change) matter for outcomes? 6) Does the duration of marriage affect child and adult outcomes? [unreadable] [unreadable] [unreadable]